Certain known tissue dissection instruments are configured for insertion through a percutaneous incision to a layer or tissue plane which can be bluntly dissected via selective expansion or other reconfiguration of the instrument in situ. Such instruments commonly incorporate a tapered tip at a distal end of an elongated body to facilitate penetration of a tissue plane as the instruments is advanced along the plane through the incision. At a selected surgical site, such instruments commonly employ a flexible balloon disposed about the periphery of the instrument near the distal end and tapered tip in order to expand the dimensions, or otherwise reconfigure the instrument under control of applied fluid pressure.
In certain surgical procedures, blunt dissection of tissue by expansion of a peripheral balloon under fluid pressure may promote unnecessary and undesirable symmetry in dissected tissue about the elongated body of the instrument, with associated trauma and reduced control on the surgical procedure. Also, the fluid pressure required to inflate the balloon is usually manually generated using a syringe-like plunger mechanism that may be difficult to manipulate to generate the required pressure.